The present invention relates to heat-sealable caps for medicament vials for use where a sterile medicament must be maintained following temporary introduction of a needle or syringe through the cap, and to apparatus and methods for filling such vials.
Medicaments such as vaccines are often stored in vials prior to use. Typically, the vials are filled with medicament, and then a cap is installed to seal the medicament in the vial. The cap is typically made of vulcanized rubber or similar resilient material that neither contaminates nor affects the contained medicament. One of the drawbacks associated with this type of filling procedure is that it is difficult to maintain the sterility of the cap during the assembly procedure. In addition, it is difficult to maintain the sterility of the vials and caps during transportation and storage prior to filling.
In order to overcome this contamination risk, the present inventor has determined that it would be desirable to first assemble the cap to the vial, sterilize the assembled cap and vial, such as by irradiation, and then fill the assembled vial by inserting a needle or like injection member through the cap and introducing the medicament through the needle into the sterilized vial. One of the drawbacks associated with this approach, however, is that when the needle or like injection member is inserted through the cap and then withdrawn, it leaves a tiny hole in the cap. The material of the cap is resilient in order to reduce the diameter of the hole, and therefore the hole is usually small enough to keep the medicament from leaking out. However, the hole typically is not small enough to prevent air or other gases from passing through the hole and into the vial, and therefore such holes can allow the medicament to become contaminated or spoiled.
It has been a practice in the pharmaceutical fields to add preservatives to medicaments, such as vaccines, in order to prevent spoilage of the medicaments upon exposure to air or other possible contaminants. Certain preservatives, however, have been determined to cause undesirable effects on patients. Consequently, many medicaments, including vaccines, are preservative free. These preservative-free medicaments, and particularly preservative-free vaccines, are subject to contamination and/or spoilage if contained within a vial wherein the cap has a needle hole as described above.
Vulcanized rubber has been determined to be a safe and effective material for manufacturing vial caps for containing numerous types of medicaments. Many other polymeric materials have not been tested for compatibility with such medicaments, and therefore cannot be used to replace the vulcanized rubber currently used to manufacture caps for medicament vials. Vulcanized rubber, however, is infusible, and therefore any needle holes in such caps are not heat-resealable in situ.
Accordingly, it is an object of the present invention to overcome the above-described drawbacks and disadvantages of the prior art.
One aspect of the present invention is directed to a resealable cap for a medicament vial comprising a base portion formed of vulcanized rubber or like material known for providing a stable environment for the medicament contained within the vial, and a resealable portion overlying the base portion. The resealable portion is made of a resealable polymeric material, such as low-density polyethylene, and can be punctured by a needle or like injection member for dispensing medicament into the vial. Upon removal of the needle, the punctured area of the resealable portion can then be heat sealed to maintain the chamber containing the medicament in a hermetically sealed condition.
Another aspect of the present invention is directed to an apparatus and method for filling a resealable vial with a predetermined medicament. The method includes the steps of providing a vial; a resealable cap including a base portion substantially infusible in response to the application of thermal energy thereto, wherein the resealable portion is compatible with the predetermined medicament for exposure to the medicament and for sealing the medicament within the vial; a resealable portion overlying the base portion and being fusible in response to the application of thermal energy thereto; and a locking member engageable with the cap and vial for securing the cap to the vial. Prior to filling the vial with medicament, the resealable cap and locking member are secured to the vial to thereby form a substantially gas-tight seal between the cap and vial. Then, the assembled cap, vial and locking member are sterilized, such as by exposure to beta or gamma radiation. A needle or like injection member is then inserted through the resealable cap and the predetermined medicament is introduced through the needle and into the interior of the vial. In the preferred embodiment of the present invention, the needle is a xe2x80x9cdouble lumenxe2x80x9d needle defining a core passageway for the introduction of the predetermined medicament therethrough and into the vial, and an annular passageway coupled in fluid communication with a vacuum source for withdrawing displaced air or other gases or vapors from the interior of the vial. Upon filling the vial with medicament, the needle is withdrawn from the cap, and sufficient thermal energy is applied to the penetrated region of the resealable portion of the cap to fuse the penetrated region and form a substantially gas-tight seal between the penetrated region and the interior of the vial. Preferably, the penetrable region of the resealable member is cauterized, such as by direct heat cauterization or laser cauterization, prior to introducing the needle through the cap, to further ensure the maintenance of sterile conditions throughout the assembly and filling processes.
One advantage of the apparatus and method of the present invention, is that the caps and locking members are secured to the vials prior to filling, thus enhancing the ability to maintain sterile conditions throughout the filling process and avoiding the need to assemble the vials in a sterile environment. As a result, the apparatus and method of the present invention significantly reduce processing time and cost in comparison to prior art vials and filling systems, and moreover, significantly increase the assurance of sterility throughout the assembly and filling processes.
Another aspect of the present invention is directed to a resealable stopper and an assembly including the resealable stopper comprising a container, the resealable stopper for sealing a predetermined substance within the container, and a locking member securing the stopper to the container. The resealable stopper includes a body defining a predetermined wall thickness in an axial direction thereof, a needle penetration region that is pierceable with a needle to form a needle aperture therethrough, and is heat resealable to hermetically seal the needle aperture by applying laser radiation from a laser source at a predetermined wavelength and power thereto. The needle penetration region defines a predetermined color and opacity that (i) substantially absorbs the laser radiation at the predetermined wavelength and substantially prevents the passage of the radiation through the predetermined wall thickness thereof, and (ii) that causes the laser radiation at the predetermined wavelength and power to hermetically seal the needle aperture formed in the needle penetration region thereof in a predetermined time period. The assembly further includes a filling machine including a needle for penetrating the resealable stopper and introducing a substance through the stopper and into the container, a substance source coupled in fluid communication to the needle for introducing the substance through the needle and into the container, and a laser source connectable in thermal communication with the resealable stopper for applying laser radiation at the predetermined wavelength and power thereto.